Device for producing a nonwoven fabric made of fiber material

ABSTRACT

A device for producing nonwoven fabric with a carding machine 3 and a nonwoven fabric layering apparatus 2. A web storage device 5 with a variable storage volume is arranged between the web producer 3 and the nonwoven fabric layering apparatus 2. The web storage device 5 is controlled by the layering belts 8, 9 of the non-woven fabric layering apparatus 2. The rotational speed VB of the layering belts 8, 9 is variable and fluctuates in rhythm with the absolute traveling speed VL of the layering carriage in the inlet area 10. The web storage device 5 is emptied and filled at the same rhythm as the web 4 by control coupling.

FIELD OF THE INVENTION

The present invention pertains to a device for producing a nonwovenfabric made of fiber material with a web producer and a nonwoven fabriclayering apparatus, which has an upper carriage and a layering carriage.

BACKGROUND OF THE INVENTION

Such a device for producing nonwoven fabric is known from GermanAuslegeschrift No. DE-AS 19 27 863. In the prior-art nonwoven fabriclayering apparatus, there is a problem with web layering in the edgearea of the layering width. The lower layering carriage must slow downits travel at these sites, come to a standstill, and then accelerateagain in the opposite direction. The web coming from the web produceris, of course, fed to the nonwoven fabric layering apparatus at aconstant speed. In the nonwoven fabric layering apparatus, the layeringbelts run at a constant speed, which causes the web to leave thenonwoven fabric layering apparatus at always the same speed. However, inthe edge areas, where the lower layering carriage has a lower speed dueto the slowing down, stopping and then accelerating, more web is layeredin the outside edges than in other areas of the layering width due tothis difference in speed.

A further development of the nonwoven fabric layering apparatus is knownfrom German Patent No. DE-PS 24 29 106. It claims to prevent the edgebuildups by having travel movements of the upper carriage and layeringcarriage being uncoupled from one another and being separatelyadjustable. Auxiliary carriages are then provided as well in order tocompensate for the resulting differences in length of the layeringbelts. The traveling speeds of the upper carriage, the layering carriageand the auxiliary carriages must then support one another in a certainratio. This requires a considerable expense for construction andcontrol. Besides, the complicated kinematics impedes the adjusting ofdifferent operating conditions of the nonwoven fabric layering apparatusfor adaptation to different types of webs or web producers.

BACKGROUND OF THE INVENTION

The task of the present invention is to design a device for producing anonwoven fabric, and in particular to a device that makes it possible toinfluence the web layering and the nonwoven fabric formation in a simpleand easily controllable manner.

In the present invention there is a web producing means which generatesa nonwoven web from a fibrous material. The web producing means producesthis nonwoven fiber at a substantially constant rate. A layeringapparatus or means receives the web and lays the web down, usually in analternating pattern. The layering means usually has a set of layeringbelts for receiving the web, and a layering carriage for discharging theweb in the alternating or reciprocating pattern. Because of themovements of the layering carriage, a take-up carriage is provided tocompensate for the changing length in the layering belts. A web storagemeans is positioned between the web producing means and the layeringmeans. When the web producing means produces the web faster than thelayering means discharges the web, the web storage means can absorb theexcess portions of the web. Likewise when the layering means dischargesthe web at a higher rate than the web producing means, the web storagemeans can release additional portions of the web stored in the webstorage means.

According to the present invention, a web storage means that has avariable storage volume is arranged between the web producer and thenonwoven fabric layering apparatus. With a corresponding storagecontrol, the web layering and the nonwoven fabric formation can herebybe specifically influenced. Edge buildups of the nonwoven fabric canespecially be prevented in a simple manner and without auxiliarycarriages or similar design interventions in the nonwoven fabriclayering apparatus. However, with the web storage means, the weblayering can also be influenced at other sites of the layering width, asspecifically more or less web is layered at certain sites, and thus, thethickness of the nonwoven fabric is changed selectively. This so-called"profiling" makes it possible to compensate for thickness errors made bya downstream processing machine, e.g., a needle loom.

There are various possibilities for controlling the web storage means.The web storage means can, e.g., be controlled independently and canachieve the compensation in edge thickness by means of the formation ofnegative slack in the web with the fabric layering apparatus other-wiserunning constantly.

In the preferred embodiment, the web storage means is controlled by thelayering belts of the nonwoven fabric layering apparatus. In this case,it is recommended to change the rotational or belt speed VB of thelayering belts at an inlet to the layering belts and to adapt the speedVB to the desired layering condition in each case rather than leaving itconstant any longer. For edge compensation, it is important to allow therotational speed VB at the inlet in this case to fluctuate in rhythmwith the absolute traveling speed VL of the layering carriage. At thereversal areas of the layering carriage with the phases of slowing down,stopping and then accelerating, the rotational speed VB of the layeringbelts at the inlet is thereby also reduced, with the result that onlylittle or no web comes out at these sites. In this manner, the edgethicknesses are arbitrarily influenced and especially prevented.

Additionally or alternatively, a specific difference in speed betweenthe rotational speed of the layering belts at the inlet and thetraveling speed of the layering carriage can be generated. Thereby, theweb runs out selectively more quickly or more slowly and produces acorresponding changed nonwoven fabric thickness. By means of the webstorage means, the web can be prevented from being stretched orcompressed by this difference in speed in the nonwoven fabric layeringapparatus.

There are various possibilities for the design of the web storage means.In the simplest form, it consists of a trough, which takes up the webwith more or less slack. Thus, the extent of the web slack determinesthe storage volume. A movable web storage means, which has a belt loopwith variable size, is recommended for a delicate web and for large feedand layering speeds of the nonwoven fabric layering apparatus. More orless web is taken up in the belt loop depending on the size.

The thickness of the web discharged from the layering means can becontrolled by a ratio between the speed of the layering carriage and thespeed at which the layering means receives the web. The thickness of theweb can also be controlled by the web storage means storing excessportions of the web, or delivering additional portions of the web.

If the web storage means is controlled via the layering belt drive ofthe nonwoven fabric layering apparatus, it is recommended to arrangethis drive on a belt deflection means of the nonwoven fabric layeringapparatus mounted on the frame. The speed of the layering belt at theinlet of the nonwoven fabric layering apparatus is thereby controlled inan especially simple manner.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a schematic lateral view of a device for producing anonwoven fabric with a non-woven fabric layering apparatus, a webstorage means and a web producer,

FIGS. 2 and 3 show alternative designs of the web storage means,

FIGS. 4 to 6 show several speed graphs for the nonwoven fabric layeringapparatus.

FIG. 7 shows the control means interacting with the layering apparatusand the storage means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 31 shows a schematic lateral view of a device for producing anonwoven fabric 1, which consists of a nonwoven fabric layeringapparatus or means 2, a web producer means 3, here represented as acarding machine, and a web storage means 5 arranged between the fabriclayering apparatus 2 and the web producer 3. In the carding machine 3, aweb 4 consisting of textile fibers is formed. This web 4 is guided tothe nonwoven fabric layering apparatus 2 via the web storage means 5.From the layering apparatus 2, the web is layered in a reciprocatingpattern on a discharging belt 30 which runs diagonally. In this case,the web 4 is layered and placed onto the discharging belt 30 in severallayers one on top of each other. The multilayer web on the dischargebelt 30 represents the so-called nonwoven fabric 31, which is then ledto a further process, e.g., to a needle loom.

The carding machine 3 consists of a rotating drum 15 and a doffingcylinder 16, which rotates in the opposite direction and strips the web4 from the drum 15. From the doffing cylinder 16, the web 4 is removedvia a doffing comb 17 and forwarded to the web storage means 5. Insteadof comb-type doffing combs 17, pull-off rollers or another suitableremoval device may also be present.

The nonwoven fabric layering apparatus 2 has two continuous layeringbelts 8, 9 that are guided in several loops. These layering belts 8, 9receive the web 4 at the inlet 10 and hold and guide the web betweenthem at least lengthwise. The two layering belts 8, 9 are guided via anupper or take-up carriage 6 and a lower layering carriage 7 and run overrotatable rollers in this case. The layering belts 8, 9 run parallel atleast in the loop area between the upper carriage 6 and the layeringcarriage 7, and they move the web 4 between them. In the embodimentshown, the upper carriage 6 and the layering carriage 7 move in oppositedirections and are coupled with one another directly or indirectly interms of drive or with regards to being driven. In the embodiment shown,the upper carriage 6 moves with half the traveling speed of the layeringcarriage 7.

As an alternative, the nonwoven fabric layering apparatus may also havecarriages moved in the same direction and, e.g., have a design similarto that in DE-AS 19 27 863 not shown.

The layering carriage 7 travels back and forth above the dischargingbelt 30 and lets the web 4 come out downwards. The speed profiles of thelayering carriage 7 are shown in the graphs in FIGS. 4B, 5B, and 6B. Thelayering carriage 7 moves over the largest area of the layering width ofdischarge belt 30 with a preferably constant traveling speed VL. At theends of its path, the so-called reversal points, the carriage 7 mustslow down, come to a standstill, change its direction of travel, andthen accelerate again. The speed VL has a preferably ramp-like course inthese so-called edge phases.

The nonwoven fabric layering apparatus 2 has a frame 14. In this frameare located rotatable rolls or rollers, over which the layering belts 8,9 are guided and turned around in the manner shown. In the exemplaryembodiment shown, only the one layering belt 8, receives the guided web4 and forwards it to the upper carriage 6. The layering belt 8 islocated at the inlet 10. As an alternative, the second layering belt 9may also be drawn up above the upper carriage 6 from the position shownin FIG. 1 and placed at the inlet 10.

The layering belts 8, 9 have a layering belt drive 13, which drives themat a layering belt speed VBA which is the same for both belts 8, 9. Thelayering belt speed VBA at the belt drive 13 and the travel movements ofthe carriages 6, 7 are superimposed during operation. As a result, thelayering belts 8, 9 move at a rotational or belt speed VB at the inlet10. Various courses of the speed VB are shown in the graphs 4A, 5A, and6A.

In the embodiment shown of the nonwoven fabric layering apparatus 2, astationary belt deflection means 12 is arranged between the twocarriages 6, 7 in the right half of the frame 14. At this beltdeflection means 12, the layering belt 8, which leads to the inlet, isguided and fixed in an omega pattern above two smaller and two largerrolls or rollers. The layering belt drive 13 for the layering belt 8 islocated on the upper roller of the two larger rollers. In the graphs,FIGS. 4C, 5C, and 6C illustrate the drive movements and the drive speedsVBA of this layering belt drive 13.

In the drive arrangement shown, it is possible for the layering beltdrive 13 to travel even essentially straight-sided ramps at the speedVBA. In the collections of graphs 4, 5, and 6, the belt rotational speedVB at the inlet 10 turns out to be the geometric sum of the speeds VBAand VL, i.e., the sum of the speeds of the layering belt drive 13 andthe layering carriage 7. A control means 34 controls the drive 13 basedon the position and speed of the layering carriage 7 to create thedesired speed VB. The control means 34 is preferably computercontrolled, but could be any device that performs the describedfunctions. In this case, the layering carriage speed VL enters with itssign dependent on the direction of travel.

A prior-art nonwoven fabric layering apparatus 2 according to the stateof the art, e.g., DE-AS 19 27 863, is shown in the collection of graphsin FIGS. 4A-4C. In this apparatus, the layering belt 8 moves at theinlet 10 at a constant rotational or belt speed VB. For this purpose,the layering belt drive 13 travels the speed profile of VBA shown inFIG. 4C. The ramps of VBA and the layering carriage speed VL compensatefor a constant VB at the time of the reversal points designated as T0,T1 and T2. At this speed ratio, the web 4 is constantly fed to thenonwoven fabric layering apparatus 2, and the web 4 is just asconstantly layered into nonwoven fabric 31 by the layering carriage 7onto the discharging belt 30. The rotational speed VB of the layeringbelts 8, 9 at the inlet 10 is, in this case, also essentially identicalto the layering carriage speed VL in the standard area of travel outsideof the phases of slowing down and accelerating. In the area of thereversing of the layering carriage 7, the initially mentioned layeringproblems for the web 4, such as the edge buildups in the nonwoven fabric31, occur due to the reduced layering carriage speed VL there.

According to the design of nonwoven fabric layering apparatus, the edgebuildups can be technically uncritical or insignificant up to a certainlevel of the layering carriage speed VL, e.g., 55 m/min, and can be cutoff on the finished nonwoven fabric 31. The edge buildups are alsocontrolled by the lower ends of the layering belts 8, 9, which arespread out over the discharging belt 30. The lower ends of the layeringbelts 8, 9 form a closed curtain above the nonwoven fabric 31 andprevent the formation of air vortices. According to the embodiment ofthe nonwoven fabric layering apparatus 2, the lower ends may also liewith a slight pressure on the nonwoven fabric 31 and hold it securely.

At higher layering carriage speeds VL, difficulties with the weblayering may occur. With the upstream web storage means 5, theseproblems are, however, specifically handled. Various embodiments of theweb storage means 5 are shown in the exemplary embodiments of FIGS. 1through 3.

FIGS. 1 and 2 show a movable web storage means 5, which is equipped witha driven 29 storage belt 18, which forms a belt loop 22 having variablesize. The web 4 is taken up in the belt loop 22. The storage volume issmaller or larger depending on the size of the loop. The movable webstorage means 5 with the storage belt 18 of FIGS. 1 and 2 are suitablefor delicate webs 4, which are supported and guided by means of thestorage belt 18.

A simple storage belt 18, which is designed as a revolving, drivencontinuous loop, is used in the exemplary embodiment of FIG. 2. It hasan excessive length, such that a lower end and/or an upper end canproduce a slack. The size of the belt loop 22 formed by the upper endchanges accordingly. In FIG. 2, the web 4 lies open in the belt loop 22.The slack is essentially determined by the belt drive and the weight ofboth the storage belt 18 and the web 4.

A tensioning device, which holds the storage belt 18 under tension, isarranged on the belt loop 22 in FIG. 1. The tensioning device has astorage carriage 23 that extends within the belt loop 22, whichpreferably hangs in the vertical direction, and can be moved back andforth in the direction of the loop. The storage carriage 23 moves by itsown weight or by a suitable drive and holds the belt loop 22 undertension. Under the belt loop 22 is located a movable tensioning carriage24 with deflecting rollers, over which the storage belt 18 runs. Thetensioning carriage 24 moves in the opposite direction of the storagecarriage 23. The tensioning carriage holds the storage belt 18 undertension by its own weight or a suitable controlled drive 36 and providesfor a compensation in the belt length.

The storage carriage 23 has a continuously revolving support belt 25,which is guided via two deflecting rollers 26 at the ends of the storagecarriage 23. By means of this, the web 4 is guided and protected betweentwo belts 18, 25 at least in the movable belt loop 22. The support belt25 may be freely movable and is then moved along by friction contactwith the moving web 4 by friction contact. As an alternative, acontrolled belt drive 35 may also be present, which drives thetensioning belt 25, taking the traveling movements of the storagecarriage 23 into consideration, in such a manner that the belts 18, 25move essentially at identical speed in the area of the belt loop 22.

In contrast, FIG. 3 shows a simple variant, in which the web storagemeans 5 consist of a concave trough 32, e.g., a sheet steel trough. Thisembodiment is more suitable for relatively stable webs 4, since thesewebs hover above the trough 32 at least occasionally with a more or lesslarge slack and thus are not constantly supported.

The web storage means 5 act as a buffer and make it possible to feedoccasionally more or less web 4 to the nonwoven fabric layeringapparatus 2 in a controlled manner. This possibility is used to preventedge buildups in the nonwoven fabric 31 in the exemplary embodimentshown.

For this purpose, the rotational speed VB of the layering belts 8, 9 atthe inlet 10 can also be changed in a preferred embodiment. Therotational speed then fluctuates at least in the inlet area 10 in rhythmwith the absolute layering carriage speed VL. FIGS. 5 and 6 illustratethis effect on the speed.

According to FIGS. 5A and 6A, even the rotational speed VB of thelayering belts 8, 9 decreases at the reversal points of the layeringcarriage 7. This results in less web 4 coming out of the layeringcarriage 7 at the reversal points. This web is temporarily stored in theweb storage means 5. Over the further path of travel of the layeringcarriage 7, the web storage means 5 is then emptied again, whereby theweb 4 is correspondingly quickly drawn off.

As FIG. 5A shows, the level of the rotational speed VB in the peak areais greater than the steady speed VZ with which the web 4 comes from theweb producer 3 and enters into the web storage means 5. However, thearea integral above the speed curve of VB is equal to the area integralabove the web feeding speed VZ within the periods T0 to T1 and T1 to T2,as well as the following periods.

The fluctuation of the rotational speed VB of the layering belts 8, 9 atthe inlet in rhythm with the layering carriage speed VL means that thespeeds behave in a qualitatively similar manner. The rotational speed VBmust, however, not drop to zero at the reversal points. After the web 4at the outlet of the layering carriage 7 swings out with a loop in amanner associated with inertia in the reversal points, it is recommendedto lower the rotational speed VB only to a mean value, for example,approximately half of the standard speed level. This results in anoptimized web layering in the edge areas.

The minimum values of the rotational speed VB must also not coincidewith the stopping of the layering carriage 7 and the zero crossing ofthe layering carriage speed VL. As FIG. 6A illustrates in the preferredembodiment, these minimum values may be staggered with regard to time.In the exemplary embodiment shown, such a speed graph arises, if thelayering belt drive 13 travels a flank that is straight, for the mostpart, at the speed VBA at the reversal areas while slowing down. In thiscase, the speed VBA reaches its zero level while slowing down later thanthe layering carriage speed VL. At the next reversal point, the speedVBA again starts correspondingly sooner than the layering carriage speedVL.

As the graphs still further illustrate, in the case of the forward pathwith positive layering carriage speed VL, i.e., if the layering carriage7 moves to the right in FIG. 1, the speed VBA of the layering belt drive13, apart from the reversal areas, equals zero. The rotational speed VBof the layering belts 8, 9 at the inlet 10 is then equal to the layeringcarriage speed VL in the area between the reversal points. VL is,however, as mentioned above, higher than the feeding speed VZ of the web4 from the web producer 3.

On the return path of the layering carriage 7, i.e., if this layeringcarriage moves to the left in the embodiment of FIG. 1 and if thelayering carriage speed VL has a negative sign, the speed VBA of thelayering belt drive 13 again increases suddenly. Even in this secondperiod between T1 and T2, the rotational speed VB and the layeringcarriage speed VL are, with the sign corrected, identical in the areabetween the reversal points. The speed VBA of the layering belt drive 13is then twice as high as the absolute values of VB and VL. The speedratios mentioned apply to both graphs of FIGS. 5 and 6.

The movable web storage means 5 of FIGS. 1 and 2 are controlled inaccordance with the rotational speed VB of the layering belts 8, 9. Thesize of the belt loop 22, including the storage volume, is herebychanged in a manner designed to meet requirements. A storage belt drive29 for the storage belt 18 is provided in the output area 27, where theweb leaves the web storage means 5 and reaches the inlet 10 of thenonwoven fabric layering apparatus 2. This drive is, for example,directly coupled with the inlet rollers 11 via a chain or the like. Bymeans of this, the output speed VA of the web storage means 5 isessentially equal to the rotational speed VB of the layering belt 8 inthe inlet 10. To maintain a certain feed tension, VB can be somewhatgreater than VA. By means of coupling the speeds VB and VA, the storagevolume also fluctuates in rhythm with the movements of travel. Insteadof a direct coupling of the rollers 11, 28, an independent drive 29,which is controlled in accordance with the rotational speed VB, may beprovided. The drive 29 may also suitably be derived from the layeringbelt drive 13.

In the feed area 19, the web 4 preferably arrives at the storage belt 18from the doffing cylinder 16 at an essentially constant feed speed VZ.At the beginning of the feed area 19, the storage belt 18 is guided viaa deflecting roller 20. The deflecting roller 20 may be provided withits own drive 21 or may be coupled directly with the doffing cylinder16. As an alternative, the deflecting roller 33, which is arranged onthe upper end of the feed area 19 in FIG. 1, may also be driven. Thestorage belt 18 is driven at the speed VZ in the feed area 19 in thecases mentioned.

The slack of the belt loop 22 changes depending on how the layeringspeed VA and the feed speed VZ react to one another. This is shown bycontinuous and dotted lines in FIG. 2. At the moment when the rotationalspeed VB of the layering belts 8, 9 drops below the feed speed VZ, theslack of the belt loop 22 increases. This is preferably the case at thereversal points of the layering carriage 7. In the exemplary embodimentof FIG. 2, the upper end of the storage belt 18 sags accordingly. In theexemplary embodiment of FIG. 1, the belt loop 22 is longer towards thebottom.

In the central area of travel of the layering carriage 7 between thephases of accelerating and slowing down, the output speed VA or therotational speed VB is again greater than the feed speed VZ, by means ofwhich the upper end of the storage belt 18 is tensioned and the webstorage means 5 is again emptied.

In a variation of the above-described exemplary embodiment, the lengthof the belt loop 22 in FIG. 1 may be actively determined by means of thelifting and lowering movements of the storage carriage 23. In this case,the drive 29 provided on the deflecting roller 28 can be omitted.Instead, the storage carrier 23 proceeds via a suitable lifting drive,which is controlled by and possibly derived from the rotational speed VBof the layering belts 8, 9. In another variation of the exemplaryembodiments of the web storage means 5 described, the web 4 that is fedmay also be covered in a suitable manner outside the belt loop 22. InFIG. 1, a revolving cover belt could be provided, e.g., above the feedarea 19.

In the above-described preferred embodiment, the web storage means 5 arecombined with the rotational speed VB of the layering belts 8, 9, whichfluctuates in rhythm with the layering carriage speed VL. In this case,the web storage means 5 is emptied or filled corresponding to therotational speed VB of the layering belts 8, 9. Proceeding in thismanner has the advantage that no negative slack is produced in the web.

As an alternative, the edge thickenings even with negative slack in theweb 4 are eliminated. A prior-art nonwoven fabric layering apparatus 2with kinematics according to the state of the art, as is shown in FIG.4, may be used for this purpose. The rotational speed VB of the layeringbelts 8, 9 is then constant. By means of the controlled emptying andfilling of the web storage means 5, which can be performed by controlmeans 34, extensions or thinning of the web may occasionally begenerated at the inlet 10. If this happens with the correct forwardmovement with regard to time, these extensions then precisely reach thedischarge of the layering carriage 7, when the carriage is located atthe reversal points of its path. In the case of discharge or immediatelyafter the layering, the extensions shrink and thereby reduce the edgebuildups. The extensions are obtained by an occasional expansion of theweb storage means 5. Subsequently, the web storage means is againcontinuously emptied, i.e., the web 4 is somewhat compressed orthickened.

The web storage means 5 can be used not only for compensating the edgethickness of the nonwoven fabric 31, but also for so-called profiling,i.e., a variation in thickness of the non-woven fabric 31 in thestandard layering area. The thickness of the nonwoven fabric changes ifthe web 4 comes out at another speed on the layering carriage 7 when thelayering carriage travels back and forth. For this purpose, a differencein speed between the traveling speed VL of the layering carriage 7 andthe rotational speed VB of the layering belts 8, 9 is produced bycontrol means 34. In addition, the rotational speed VB of the layeringbelts 8, 9 compared with the layering carriage speed VL in the layeringarea between the reversal points is preferably changed. The profilingcan be combined with the above-described edge thickness compensation orcan even take place independently.

Advantageously, even during the profiling, the output speed VA of theweb storage means 5 is coupled with the rotational speed VB of thelayering belts 8, 9. By means of this, a negative slack of the web 4 inthe nonwoven fabric layering apparatus 2 can be avoided.

If the rotational speed VB of the layering belts 8, 9 is higher than thetraveling speed VL of the layering carriage 7, more web 4 comes out atthe discharge, which leads to a selective thickening of the layerednonwoven fabric 31. Conversely, if VB is lower than VL, less web 4 islayered, and thus, a selective thinning of the nonwoven fabric 31 isproduced. In the weight assessment, the thinnings and thickenings arecompensated, such that, overall, just as much web 4 is layered over thelayering width, as is fed to the nonwoven fabric layering apparatus 2 onthe feed side. By means of the upstream web storage means 5, thesefluctuations in the doffing of the nonwoven fabric layering apparatus 2compared with the preferably constantly feeding carding machine 3 can becompensated.

In a variation of the above-described technique used in the profiling,the nonwoven fabric layering apparatus 2 can also run with constantkinematics according to the state of the art in accordance with FIG. 4.By means of controlled emptying or filling, preferably by the controlmeans 34 controlling drive 29 the independently driven web storage means5 then produces thinnings or thickenings in the web 4, which then movethrough the nonwoven fabric layering apparatus 2 and come out and arelayered at the desired sites of the layering width on the layeringcarriage 7 by observing a suitable forward movement with regard to time.

In another variant, the layering carriage speed VL compared with therotational speed VB of the layering belts can be changed for theprofiling. In this case, the web storage means 5 is controlled by thelayering carriage drive or in another suitable manner. In bothabove-mentioned variants, a combination of the profiling with theinitially described edge thickness compensation is possible. Moreover,the embodiments described may be arbitrarily combined.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

    ______________________________________                                        LIST OF REFERENCE NUMBERS:                                                    ______________________________________                                         1         Device for producing nonwoven fabric                                2         Nonwoven fabric layering apparatus                                  3         Web producer, carding machine                                       4         Web                                                                 5         Web storage means, compensator                                      6         Upper carriage                                                      7         Layering carriage                                                   8         Layering belt                                                       9         Layering belt                                                      10         Inlet                                                              11         Inlet rollers                                                      12         Belt deflection means                                              13         Layering belt drive                                                14         Frame                                                              15         Drum                                                               16         Doffing cylinder                                                   17         Doffing comb                                                       18         Storage belt                                                       19         Feed area                                                          20         Deflecting rollers                                                 21         Drive                                                              22         Belt loop                                                          23         Tensioning device, storage carriage                                24         Tensioning carriage                                                25         Support belt                                                       26         Deflecting roller                                                  27         Output area                                                        28         Output roller                                                      29         Drive                                                              30         Discharging belt                                                   31         Nonwoven fabric                                                    32         Trough                                                             33         Deflecting roller                                                  VA         Output speed (web storage means)                                   VB         Rotational speed (layering belt)                                   VAB        Speed of the layering belt drive                                   VL         Layering carriage speed                                            VZ         Feeding speed (web producer)                                       ______________________________________                                    

We claim:
 1. A device for producing nonwoven fabric, the devicecomprising:a web producing means for generating a nonwoven web fromfiber; a nonwoven fabric layering means for receiving the web from saidweb producing means and for layering the web, said nonwoven fabriclayering means including a takeup carriage and a reciprocating layeringcarriage, said layering carriage moving in a reciprocating pattern; webstorage means positioned between said web producing means and saidnonwoven fabric layering means, said web storage means storing avariable volume of the web.
 2. A device in accordance with claim 14,wherein:said web storage means stores said variable volume dependent ona speed VB of the web at an inlet of said nonwoven fabric layeringmeans.
 3. A device in accordance with claim 2, wherein:said nonwovenfabric layering means varies said speed VB dependent on an absolutespeed of said layering carriage.
 4. A device in accordance with claim 1,wherein:said web storage means stores said variable volume dependent ontravel movements of said layering carriage.
 5. A device in accordancewith claim 1, wherein:said web storage means includes a storage belt forreceiving the web, said storage belt forming a storage loop of variablesize.
 6. A device in accordance with claim 5, wherein:said web storagemeans also includes a tensioning means for tensioning said storage belt.7. A device in accordance with claim 6, wherein:said tensioning meansincludes a storage carriage with a support belt revolving aroundrollers.
 8. A device in accordance with claim 7, wherein:said tensioningmeans includes a tensioning carriage positioned outside said storageloop and movable opposite to movements of said storage carriage.
 9. Adevice in accordance with claim 8, wherein:one of said storage carriage,said support belt and said tensioning carriage includes a controlleddrive.
 10. A device in accordance with claim 5, wherein:said storagebelt includes a storage belt drive for driving said storage belt at aposition adjacent said web producing means and at a speed substantiallyequal to an exit speed of the web from said web producing means.
 11. Adevice in accordance with claim 5, wherein:said storage belt includes astorage belt drive for driving said storage belt at a position adjacentsaid nonwoven fabric layering means and at a speed substantially equalto a speed VB of the web at an inlet of said nonwoven fabric layeringmeans.
 12. A device in accordance with claim 5, wherein:said storagebelt has an output roller coupled with an input roller of said nonwovenfabric layering means.
 13. A device in accordance with claim 1wherein:said nonwoven fabric layering means includes a layering beltwith a belt deflection means, a layering belt drive for said layeringbelt being mounted on said belt deflection means.
 14. A device forproducing nonwoven fabric, the device comprising:a web producing meansfor generating a nonwoven web from fiber material at a first rate; anonwoven fabric layering means for receiving the web from said webproducing means and layering the web in a reciprocating pattern at avariable rate with respect to said first rate of said web producingmeans, said nonwoven fabric layering means including layering belts, atakeup carriage and a layering carriage, said layering carriage movingin said reciprocating pattern and changing speed during moving in saidreciprocating pattern, said takeup carriage means compensating saidlayering belts for moving of said layering carriage; web storage meanspositioned between said web producing means and said nonwoven fabriclayering means, said web storage means storing excess portions of theweb when said variable rate is less than said first rate and releasingsaid excess portions of the web when said variable rate is greater thansaid first rate.
 15. A device in accordance with claim 14, wherein:saidnonwoven fabric layering means and said web storage means include meansfor changing said variable rate of layering the web.
 16. A device forproducing nonwoven fabric, the device comprising:a web producing meansfor generating a nonwoven web from fiber material at a first rate; anonwoven fabric layering means for receiving the web from said webproducing means and discharging the web in a reciprocating pattern, saidnonwoven fabric layering means including a layering carriage, saidlayering carriage uniformly moving in said reciprocating pattern; webstorage means positioned between said web producing means and saidnonwoven fabric layering means, said web storage means bufferingdifferences in a rate of the web generated by said web producing meansand received by said layering means; control means for varying an amountof the web discharged by said layering means dependent on a position oflayering carriage in said reciprocating pattern.
 17. A device inaccordance with claims 16, wherein:said control means also variesdischarge of the web dependent on a speed of said layering carriage. 18.A device in accordance with claim 16, wherein:said control means variesdischarge of the web by varying a speed of the web in said layeringmeans.
 19. A device in accordance with claim 16, wherein:said layeringmeans includes first and second layering belts, said layering beltsinteracting with said layering carriage, said layering means including adrive means for moving said layering belts; said control meanscoordinating said drive means with said movements of said layeringcarriage to vary discharge of the web.
 20. A device in accordance withclaim 16, wherein:said control means varies a volume of the webdelivered from said storage means to said layering means to varydischarge of the web from said layering means.
 21. A device inaccordance with claim 20, wherein:said control means varies the volumeof the web by delivering the web from said storage means at a speeddifferent than said layering means receives the web.